In recent years, memory systems comprising a nonvolatile memory are widely used.
As one of such memory systems, a solid state drive (SSD) comprising a NAND flash memory is known. SSD is used as a main storage of various computing devices.
Recently, it is required that a huge amount of data be stored efficiently in a storage.
As technology for improving storage efficiency, de-duplication is known.
But, in the conventional de-duplication technology, a technique of saving a memory source required for storing management data necessary for de-duplication is not taken into consideration.